Also Monday, European Union foreign ministers said they were keeping an arms embargo against Syria in place for three more months, blocking a push by some to ease restrictions so some countries could arm the rebels.

An EU official said before the meeting in Brussels to decide the matter that Britain was pushing to ease the embargo. Several foreign ministers from other countries said they opposed the move.

Syria's opposition has long appealed for military aid, calling it the only way to turn the tide against Assad's forces.

But the U.S. and other countries have resisted such a move, saying there is no way to control how the arms are used and fearing they could fall into the hands of extremists.

"We are convinced that a lifting of the weapons embargo would not be reasonable," said German Foreign Minister Guido Westerwelle. "This would only lead to a new arms race in Syria. This would mean a further escalation of violence with many, many more victims."

Inside Syria on Monday, rebels overran a government checkpoint on the road the country's second-largest airport and briefly occupied a fuel station inside of it, activists said.

Rebels launched an offensive to capture the Aleppo international airport and adjacent Nairab military air base last week and have since stormed the army based charged with protecting the area.

The fall of the airport would be a turning point in the fate of the city, Syria's largest, which is now heavily damaged and divided between rebel- and government-controlled zones.

The government has not been able to fly in supplies for weeks because of the fighting.

The head of the Britian-based Syrian Observatory for Human Rights said Monday that the government has managed to bring dozens of vehicles and thousands of troops to the town of Safira, southeast of Aleppo but that heavy fighting has kept them from pushing further towards Aleppo.

Abdul-Rahman, who relies on a network of contacts inside Syria, said the army killed more than 200 members of the Jabhat al-Nusra group over the last two weeks as it pushed toward Safira. The U.S. has designated Jabhat al-Nusra a terrorist organization.

For its part, the Syrian government said its forces fought and killed "armed terrorists" in the provinces of Idlib, Homs and Aleppo. Syria blames the conflict on an international conspiracy carried out by terrorists to weaken the country.

Also Monday, the Lebanese militant group Hezbollah announced that one of its fighters had been killed while doing "his jihadist duty." It gave no further details on his death.

The announcement followed reports from Syrian activists and a Lebanese official near the Syrian border that at least two Hezbollah fighters had been killed in sectarian clashes near the Syrian town of Qusair on Saturday.

Hezbollah declined to comment on the clashes, and it could not be confirmed that the fighter buried Monday was killed in Syria.